An indirect tire pressure monitoring system uses the wheel rolling radius as an indicator of low tire pressure. When extra load is put in the trunk of a car, the load distribution in the car will change. This will affect the rolling radius which in its turn will be confused with a change in the tire pressure. To avoid this phenomenon, the load distribution has to be estimated. In this thesis methods for estimating the pitch angle of a car and an offset in the pitch angle caused by changed load distribution are presented and when an estimate is derived, a load distribution can be derived. Alot of available signals are used but the most important are the longitudinal accelerometer signal and the acceleration at the wheels derived from the velocity of the car. A few ways to detect or compensate for a non-zero road grade are also presented. Based on the estimated offset, a difference between the front and rear axle heights in the vehicle can be estimated and compensating for the changed load distribution in an indirect tire pressure monitoring system will be possible.

The wind industry is always seeking ways to better understand the performance of a wind turbine and improve its efficiency. During the operation phase and maintenance, wind turbines go through regular optimization. Due to the regular change in wind speed and direction, wind turbines need to be regulated and positioned accordingly. For a specific wind speed, there are a specific set of pitch angle positions. The study aims to quantify the errors in pitch angle positions and validate how much would the loss be if it deviates from its ideal pitch angle position. In this study, airfoil data from an NREL 5 MW turbine is used. Qblade is used in the simulation for error estimation. The simulation is based on BEM theory. A wind turbine blade is developed based on the given airfoil data. Multi-parameter BEM simulation is conducted for a range of wind speed, pitch angle, and rpm. Later the ideal pitch angle position for each wind speed bin is recorded. During the simulation process, downscaling the 5 MW to a 1.5 MW turbine was executed. Validation of the downscaling method was also executed. It showed good agreement with the obtained SCADA data of a working turbine. Later, pitch angle errors are introduced in the simulation.  The results are presented in two cases. Case 1 showed that at below-rated wind speed, there is a significant loss in power production if the error in pitch angle up to 1 degree.  Case 2 also shows error up to 5 degrees in region 2. This study contributes to a better understanding of the effect of pitch angle errors and their loss of power. This study took into account steady wind condition only and does not include climatic conditions or turbulence. A further study focusing on simulating in a high-fidelity setting, including real-time wind or topography conditions, is recommended to achieve a further understanding of the pitch angle errors in a wind turbine.

Made available in DSpace on 2016-08-31T13:33:44Z (GMT). No. of bitstreams: 1 FranciscoCBS_DISSERT.pdf: 1910035 bytes, checksum: 49a978c792393d00663be9720c45ef02 (MD5) Previous issue date: 2015-06-26 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The development of a mathematical model for a system of wind power generation is complex, can be strongly affected by the wind variation and it s a non-linear problem. Due to these characteristics the analysis can be performed using a control system based on fuzzy logic, which improves a better adjust of the system to be controlled. In this paper, the performance of a variable-speed wind turbine controlled by a classic proportional controller (CPC), and a fuzzy logic controller (FLC) to adjust the angle of inclination of the blades is analyzed. In this case, it s possible to verify the effectiveness of the application of fuzzy logic, the ability to avoid fluctuations and improvement of the quality of electric power output, regardless of the original features of the proportional control applied. The CPC and the FLC were implemented using the Fuzzy Logic ToolboxTM and SIMULINK® software packages available in MATLAB®. The results show that the application of fuzzy logic to adjust the parameters of a controller can improve the dynamic performance of the wind turbine with respect to reducing the onset of fatigue loads, weather fluctuations and stabilization of electric power output / O desenvolvimento de um modelo matemático para um sistema de geração de energia eólica, pode se tornar uma tarefa muito complexa, podendo ser fortemente dependente da variação do vento, além de se caracterizar como um problema não linear. Devido a estas características, a análise pode ser realizada utilizando um sistema de controle baseado em Lógica Fuzzy (LF), o que poderia promover melhor perfomance ao sistema a ser controlado. No presente trabalho, o desempenho de uma turbina eólica de velocidade variável controlado por um controlador proporcional clássico (CPC) e um controlador fuzzy (FLC) para promover ajuste ao ângulo pitch são analisados. Dessa forma, é possível verificar a eficácia da aplicação LF, sua capacidade de evitar flutuações e melhorar da qualidade da potência gerada, independentemente das cndições de vento ao qual o sistema está submetido. O CPC e o FLC foram implementados utilizando Fuzzy Logic ToolboxTM e Simulink®, toolboxs disponíveis no software MATLAB®. Os resultados mostram que a aplicação em questão pode efetivamente contirbuir para a melhoria do desempenho dinâmico da turbina no tocante a redução de oscilações, máximo sobresinal e tempode acomodação

When it comes to design a wind turbine rotor, several parameters have to be taken into account. The present work focuses on the inclination of the blades with respect to the rotor plane, namely the pich angle. The main goal of the project was to design a small-scale wind turbine rotor for wind tunnel tests and in this thesis the optimization of a first prototype is presented. The characterization of the performances was carried out by coupling two different approaches: an experimental and a numerical one. For the experimental part, a proper setup was built and the wind turbine model was tested in a wind tunnel. The results were compared with a Blade Element Momentum theory code developed in Python, that involved also CFD simulations to assess the aerodynamic properties of the blade sections. The analysis characterized the performances at variable collective pitch in terms of power and thrust coefficient, showing that the intitial blade design was not the optimal one. Therefore, the optimal pitch angle that maximize the power porduction was found for variable conditions. The second part of the experiments focused on the case of pitch unbalanced and the potential risks connected to it. As a result, the analysis demonstrated that any kind of pitch unbalance generates losses in the power production and may lead to a possible increase of the thrust. To compare the results, a modified BEM code was developed by assuming an axisymmetric axial induction factor. Finally, an additional analysis on the wind turbine oscillations was made, finding a connection between lateral vibrations and rotor unbalance and revealing the resonance frequency of the structure.

Ventilation is a critical task in underground mining operation. Lack of a good ventilation system causes accumulation of harmful gases, explosions, and even fatalities. A proper ventilation system provides adequate fresh air to miners for a safe and comfortable working environment. Fans, which provide air flow to different faces of a mine, have great impact in ventilation systems. Thus, selection of appropriate fans for a mine is the acute task. Unsuitable selection of a fan decreases safety and production rate, which increases capital and operational costs. Moreover, pitch angle of fans&rsquo / blades plays an important role in fan&rsquo / s efficiency. Therefore, selection of a fan and its pitch angle, which yields the maximum efficiency, is an emerging issue for an efficient mine ventilation. The main objective of this research study is to provide a decision making methodology for the selection of a main fan and its appropriate pitch angle for efficient mine ventilation. Nowadays, analytical hierarchy process as multi criteria decision making is used, and it yields outputs based on pairwise comparison. On the other hand, Fuzzy Logic as a soft computing method was combined with analytical hierarchy process and combined model did not yield appropriate results / because Fuzzy AHP increased uncertainty ratio in this study. However, fuzzy analytical hierarchy process might be inapplicable when it faces with vague and complex data set. Soft computing methods can be utilized for complicated situations. One of the soft computing methods is a Neuro-Fuzzy algorithm which is used in classification and DM issues. This study has two phases: i) selection of an appropriate fan using Analytical Hierarchy Process (AHP) and Fuzzy Analytical Hierarchy Process (Fuzzy AHP) and ii) selection of an appropriate pitch angle using Neuro-Fuzzy algorithm and Fuzzy AHP method. This study showed that AHP can be effectively utilized for main fan selection. It performs better than Fuzzy AHP because FAHP contains more expertise and makes problems more complex for evaluating. When FAHP and Neuro-Fuzzy is compared for pitch angle selection, both methodologies yielded the same results. Therefore, utilization of Neuro-Fuzzy in situation with complicated and vague data will be applicable.

This thesis deals with the design of electrical control for a constant speed propeller. The objective of this paper is to demonstrate the propeller governor design process on a case example of a DMP-3 propeller paired with a Rotax 912 ULS, using knowledge of flight mechanics, electrical engineering and automation. The scope of this thesis addresses the problems of propeller pitch control using an electrically driven linear actuator. In conclusion, this paper compares the benefits of the DMP-3 constant speed propeller, considering its use in existing airplanes within the UL-2 and CS-LSA category. Furthermore, it evaluates the capabilities of the proposed electronic governor, and outlines possibility of further development in this field.

This work is focused on the development of a thorough study about ISO standards focused on the vehicle dynamics, standardized tests of vehicle dynamics and measured variables that allow us to describe and model the behaviour of riding vehicles properly. In the Appendix A of the thesis, there is a list of all known ISO standards dealing with given topic. The standard ISO 15037-1 Road vehicles – Vehicle dynamics test methods, Part 1: General conditions for passenger cars is described in detail, including the forms for test reports and the Appendix C and D. In the thesis, there is also described a model of minimal needed measuring system that is still in good accordance with the standard ISO 15037-1 and fulfills all its requirements. Detailed description of all used sensors that are used to measure required variables is given, as well as a short description of all sensors that are used for measurement of other variables. After that, measurement abilities of the instrumentation of measuring system RIO used in ÚADI FSI Brno is compared and confronted with requirements given by the standard, to see, if all given criteria are properly fulfilled. Because of the fact that standard-given criteria are quite mild, while the equipment of the faculty is high-level technology, mostly made directly for measuring of dynamic parameters of the vehicles, including racing vehicles, the system is in full accordance with the standard ISO 15037-1.